The present invention is related to a membrane probe card, and, more particularly, to a replaceable modularized membrane probe card, wherein a membrane assembly is replaceable.
Integrated circuits are typically formed on a semiconductor substrate by a series of processes, such as deposition, photolithography, and etching processes. The conductive materials, dielectric materials, and semiconductor materials having patterns or non-patterns are formed successively on a major surface of the semiconductor substrate for making an integrated circuit pattern. Recently, significant advances have been obtained to meet the need for the Ultra Large-Scale Integrated (ULSI) circuits. Semiconductor integrated circuits currently being manufactured follow ultra high-density design rules. The performance and integrity of each die circuit must be tested before the dies are cut out of the wafer and package. Testing is typically done by conductive probe card apparatus that makes physical and electrical contact with the die pads.
As shown in FIG. 1 and FIG. 2, side section and bottom plan views of a prior art high density probe card are illustrated. An epoxy ring printed circuit probe card 2 includes an aluminum ring 12, an epoxy resin 14, and probes 4 that are arranged into a lower row 4a and an upper row 4b. The probe wires 4c extend radially outwardly to traces 6 on the lower surface 8 of the probe card 2. The drawback and ultimate density limitation for the probe card 2 is that the traces 6 are formed on the same lower surface 8 and must be located at the same radial distance. The single set of traces carries all of the connections for all of the probes 4. In order for there to be sufficient spacing for radial traces 6, they must be radially spaced from the central opening 10 a sufficient distance to allow for minimum trace width and for insulative spacing between the traces 6. This close proximity leads directly to shorts and to undesirable coupling and electrical interference between the probes 4. Therefore, with the limited size of the probe card and the limited radial distances of the probe traces from center, and with the resultant construction having closeness of adjacent traces, it is extremely difficult to construct a high density probe card of the conventional type.
Besides, there are many disadvantages of the above-mentioned probe card. (1) The dimension of the chip shrinks as the density of integrated circuit increases, preventing the pads from being a layout in a matrix mode, limited by the arrangement of the probes. (2) Avoiding shorts and electrical interference between the probes, the pitch between pads is alternatingly wide. (3) The probes scrape the conductive pads after first contact with the conductive pads and cuts through any thin film of aluminum oxide or other metallic oxide. The conductive pads are damaged causing the yields of the subsequent processes to decrease and the testing variations to increase. (4) The vertical positioning of the probe tips of a probe card is not in planarization, thereby all probes make electrical connection at the different times causing different contact forces. Therefore, the ohmic contacts between the probe tips and conductive pads are influenced. (5) The oxidized probe tips of the probe card or the oxide film residue on the surface of the conductive pads are both contaminated influencing the electrical character of the probe card. Therefore, the probe card must be maintained and replaced constantly. (6) The probes of a probe card are conventionally mounted by solder, so that the solder must be removed before the probes are replaced when any probes are damaged. However, this procedure is performed by a number of apparatus, thereby the maintenance of the probe card is difficult and time-consuming. (7) The electric resistance of the conventional probe card is relative high limiting the test frequency, thereby it cannot be applied to a high frequency test.
There is a need to provide a modularized membrane probe card to overcome the disadvantages of the conventional probe as mentioned above. A plurality of bumps on the membrane assembly with circuit patterns is used to electrically connect to the pads of the tested wafer. The membrane probe card is replaceable for simply and easily changing membrane assembly on production line by an operator. The operator changes the membrane assembly according to the variable integrated circuit layout without changing the whole probe card, which decreases cost and maintenance time.
A general object of the present invention is to provide a membrane probe card, which is a module type for reducing the cost of the apparatus, and saving time for maintenance.
Another object of the present invention is to provide a membrane probe card for testing high-density integrated circuits having a matrix type layout.
A membrane probe card is disclosed according to the present invention, which comprises a pressure mechanism, a membrane assembly, and a printed circuit board. The pressure mechanism comprises an upper-housing, a spring system, and support block. The upper-housing has a plurality of first oriented openings, a plurality of second oriented openings, and a plurality of third oriented openings. The plurality of first oriented openings is used to connect the pressure mechanism and the membrane assembly to the printed circuit board to constitute the membrane probe card. The plurality of second oriented openings and the plurality of third oriented openings are used to connect the upper-housing, the spring system, and the support block to make up the stable pressure mechanism. The support block is one major feature of the present invention, which comprises a support base, a support ring, and a support block flange. The support ring has slight flexibility for assisting the spring system to result in the support base having a vertically traveling distance.
The membrane assembly is one other feature of the present invention, which is replaceable. The membrane assembly comprises a plurality of membrane regions, a membrane probe region, and a plurality of membrane connection regions. A plurality of metal bumps under the membrane probe region is used for an electrical connection to a tested wafer. A plurality of metal bumps under the plurality of the membrane connection regions is used for electrically connecting to the printed circuit board. The plurality of the membrane regions having circuit patterns thereon connect electrically the plurality of the membrane connection regions to the membrane probe region.